The max number of most items and healing items is 999 for D/P/Plat.
You can only get that many rare candies by using an Action Replay.
You get it from the action replay
493
200 POKEMON 200 POKEMON
There are 18 Fire Attacks in Pokemon Diamond, Pearl and Platinum.
490
110
493
110
there is only 1 region in platinum and that is sinnoh
3
1